need to sort my sounds

I have a (EG) 96 Civic Lsi coupe. When i got the car a month a go, it had already had a sony head unit installed and a set of Kenwood rear speakers. The Head unit has an out put of 4X40. which is ok i think, and it has RCA output.
The problem is i have to have most of the sound coming from the back of the car through the rear speakers, because the standard fronts are crap!!!!
I want to upgrade the front speakers but i found that they are very shallow fitting because the windows come down along way. Does any1 no of any good shallow fitting speakers? or will i need new door builds?
Also are 12" ported Vibe subs any good, with built in amp. I lissen to lots of different music, from UK garage to Hard House tracks.
(Need some soundz to go crusin with)